From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:53947) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Yfgvl-00017N-IW for qemu-devel@nongnu.org; Tue, 07 Apr 2015 23:45:35 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1Yfgvg-0007XQ-Im for qemu-devel@nongnu.org; Tue, 07 Apr 2015 23:45:33 -0400 Received: from mail-pa0-f49.google.com ([209.85.220.49]:36174) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Yfgvg-0007XD-2Z for qemu-devel@nongnu.org; Tue, 07 Apr 2015 23:45:28 -0400 Received: by pabsx10 with SMTP id sx10so100608452pab.3 for ; Tue, 07 Apr 2015 20:45:26 -0700 (PDT) Message-ID: <5524A44F.2010905@ozlabs.ru> Date: Wed, 08 Apr 2015 13:45:19 +1000 From: Alexey Kardashevskiy MIME-Version: 1.0 References: <1427779727-13353-1-git-send-email-aik@ozlabs.ru> <1427779727-13353-5-git-send-email-aik@ozlabs.ru> <20150408020121.GB28909@voom.redhat.com> In-Reply-To: <20150408020121.GB28909@voom.redhat.com> Content-Type: text/plain; charset=koi8-r; format=flowed Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH qemu v5 04/12] spapr_pci_vfio: Enable multiple groups per container List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: David Gibson Cc: Alex Williamson , qemu-ppc@nongnu.org, qemu-devel@nongnu.org, Alexander Graf On 04/08/2015 12:01 PM, David Gibson wrote: > On Tue, Mar 31, 2015 at 04:28:39PM +1100, Alexey Kardashevskiy wrote: >> This enables multiple IOMMU groups in one VFIO container which means >> that multiple devices from different groups can share the same IOMMU >> table (or tables if DDW). >> >> This removes a group id from vfio_container_ioctl(). The kernel support >> is required for this; if the host kernel does not have the support, >> it will allow only one group per container. The PHB's "iommuid" property >> is ignored. >> >> This adds a sanity check that there is just one VFIO container per >> PHB address space. >> >> Signed-off-by: Alexey Kardashevskiy > > [snip] >> diff --git a/hw/vfio/common.c b/hw/vfio/common.c >> index b012620..99e1900 100644 >> --- a/hw/vfio/common.c >> +++ b/hw/vfio/common.c >> @@ -915,21 +915,23 @@ void vfio_put_base_device(VFIODevice *vbasedev) >> close(vbasedev->fd); >> } >> >> -static int vfio_container_do_ioctl(AddressSpace *as, int32_t groupid, >> +static int vfio_container_do_ioctl(AddressSpace *as, >> int req, void *param) >> { >> - VFIOGroup *group; >> VFIOContainer *container; >> - int ret = -1; >> + int ret; >> + VFIOAddressSpace *space; >> >> - group = vfio_get_group(groupid, as); >> - if (!group) { >> - error_report("vfio: group %d not registered", groupid); >> - return ret; >> - } >> + space = vfio_get_address_space(as); >> + container = QLIST_FIRST(&space->containers); > > So getting the container handle from the address space, rather than > the group id certainly makes more sense to me. > >> - container = group->container; >> - if (group->container) { >> + if (!container) { >> + error_report("vfio: container is not set"); >> + return -1; >> + } else if (QLIST_NEXT(container, next)) { >> + error_report("vfio: multiple containers per PHB are not supported"); >> + return -1; > > But if only one PHB per address space is possible, why is the > containers field a list in the first place? Historically the list was added in 3df3e0a5872 (the patch of yours :) ). In theory we could implement spapr-pci-bridge (derived from pci-bridge) with isolation capability (i.e. its own LIOBN/DMA window), in this case there could be multiple containers per PHB address space. Other archs could want multiple containers for some other reason. It would help me a lot if you remembered why you kept the list at the first place :) For now I guess I'll move the next patch ("vfio: spapr: Move SPAPR-related code to a separate file") before this one, do s/vfio_container_do_ioctl/ vfio_spapr_container_do_ioctl/ and move it to hw/vfio/spapr.c. Makes sense? >> + } else { >> ret = ioctl(container->fd, req, param); >> if (ret < 0) { >> error_report("vfio: failed to ioctl %d to container: ret=%d, %s", >> @@ -937,12 +939,10 @@ static int vfio_container_do_ioctl(AddressSpace *as, int32_t groupid, >> } >> } >> >> - vfio_put_group(group); >> - >> return ret; >> } >> >> -int vfio_container_ioctl(AddressSpace *as, int32_t groupid, >> +int vfio_container_ioctl(AddressSpace *as, >> int req, void *param) >> { >> /* We allow only certain ioctls to the container */ >> @@ -957,5 +957,5 @@ int vfio_container_ioctl(AddressSpace *as, int32_t groupid, >> return -1; >> } >> >> - return vfio_container_do_ioctl(as, groupid, req, param); >> + return vfio_container_do_ioctl(as, req, param); >> } >> diff --git a/include/hw/vfio/vfio.h b/include/hw/vfio/vfio.h >> index 0b26cd8..76b5744 100644 >> --- a/include/hw/vfio/vfio.h >> +++ b/include/hw/vfio/vfio.h >> @@ -3,7 +3,7 @@ >> >> #include "qemu/typedefs.h" >> >> -extern int vfio_container_ioctl(AddressSpace *as, int32_t groupid, >> +extern int vfio_container_ioctl(AddressSpace *as, >> int req, void *param); >> >> #endif > -- Alexey